from __future__ import annotations

import os
from dataclasses import dataclass
from pathlib import Path

MAX_ARCHIVE_RETENTION_DAYS = 2


def _as_bool(name: str, default: bool) -> bool:
    value = os.getenv(name)
    if value is None:
        return default
    return value.strip().lower() in {"1", "true", "yes", "on"}


def _as_int(name: str, default: int, minimum: int = 1) -> int:
    value = os.getenv(name)
    if value is None:
        return default
    try:
        return max(minimum, int(value))
    except ValueError:
        return default


@dataclass(frozen=True, slots=True)
class Settings:
    project_root: Path
    data_dir: Path
    database_path: Path
    work_dir: Path
    artifacts_dir: Path
    reports_dir: Path
    host: str
    port: int
    worker_enabled: bool
    worker_concurrency: int
    fetch_concurrency: int
    queue_poll_seconds: float
    lease_seconds: int
    allow_private_networks: bool
    allow_nonstandard_ports: bool
    respect_robots: bool
    default_retention_days: int
    max_retention_days: int
    max_pages_cap: int
    max_depth_cap: int
    max_bytes_cap: int
    max_duration_seconds_cap: int
    max_response_bytes: int
    max_files: int
    max_external_hosts: int
    max_redirects: int
    user_agent: str
    proxy_url: str | None

    @classmethod
    def from_environment(cls) -> Settings:
        project_root = Path(__file__).resolve().parents[1]
        data_dir = Path(os.getenv("SITEHARBOR_DATA_DIR", project_root / "data")).expanduser()
        if not data_dir.is_absolute():
            data_dir = project_root / data_dir
        max_retention_days = min(
            _as_int("SITEHARBOR_MAX_RETENTION_DAYS", MAX_ARCHIVE_RETENTION_DAYS),
            MAX_ARCHIVE_RETENTION_DAYS,
        )
        default_retention_days = min(
            _as_int("SITEHARBOR_DEFAULT_RETENTION_DAYS", MAX_ARCHIVE_RETENTION_DAYS),
            max_retention_days,
        )

        return cls(
            project_root=project_root,
            data_dir=data_dir,
            database_path=data_dir / "siteharbor.sqlite3",
            work_dir=data_dir / "work",
            artifacts_dir=data_dir / "artifacts",
            reports_dir=data_dir / "reports",
            host=os.getenv("SITEHARBOR_HOST", "127.0.0.1"),
            port=_as_int("SITEHARBOR_PORT", 8787),
            worker_enabled=_as_bool("SITEHARBOR_WORKER_ENABLED", True),
            worker_concurrency=_as_int("SITEHARBOR_WORKER_CONCURRENCY", 1),
            fetch_concurrency=_as_int("SITEHARBOR_FETCH_CONCURRENCY", 6),
            queue_poll_seconds=max(0.1, float(os.getenv("SITEHARBOR_QUEUE_POLL_SECONDS", "0.75"))),
            lease_seconds=_as_int("SITEHARBOR_LEASE_SECONDS", 120, minimum=15),
            allow_private_networks=_as_bool("SITEHARBOR_ALLOW_PRIVATE_NETWORKS", False),
            allow_nonstandard_ports=_as_bool("SITEHARBOR_ALLOW_NONSTANDARD_PORTS", False),
            respect_robots=_as_bool("SITEHARBOR_RESPECT_ROBOTS", True),
            default_retention_days=default_retention_days,
            max_retention_days=max_retention_days,
            max_pages_cap=_as_int("SITEHARBOR_MAX_PAGES", 1_000),
            max_depth_cap=_as_int("SITEHARBOR_MAX_DEPTH", 12),
            max_bytes_cap=_as_int("SITEHARBOR_MAX_BYTES", 1024 * 1024 * 1024),
            max_duration_seconds_cap=_as_int("SITEHARBOR_MAX_DURATION_SECONDS", 3_600),
            max_response_bytes=_as_int("SITEHARBOR_MAX_RESPONSE_BYTES", 32 * 1024 * 1024),
            max_files=_as_int("SITEHARBOR_MAX_FILES", 5_000),
            max_external_hosts=_as_int("SITEHARBOR_MAX_EXTERNAL_HOSTS", 20),
            max_redirects=_as_int("SITEHARBOR_MAX_REDIRECTS", 10),
            user_agent=os.getenv(
                "SITEHARBOR_USER_AGENT",
                "SiteHarbor/0.1 (+local standalone capture; respect robots.txt)",
            ),
            proxy_url=os.getenv("SITEHARBOR_PROXY_URL", "").strip() or None,
        )

    def ensure_directories(self) -> None:
        for directory in (self.data_dir, self.work_dir, self.artifacts_dir, self.reports_dir):
            directory.mkdir(parents=True, exist_ok=True)


settings = Settings.from_environment()